Influence of the dispersants and sintering process on the properties of Si2N2O ceramics via digital light processing

As one of the most widely used technologies in ceramic additive manufacturing, digital light processing (DLP) enables the precise formation of ceramic products with complex structures. Current studies on Si 2 N 2 O ceramics are mainly focused on the reactive sintering of Si 2 N 2 O ceramics and the traditional molding and processing processes, and investigations on the DLP of Si 2 N 2 O ceramics are lacking. In this study, Si 2 N 2 O ceramics with complex structures were prepared by DLP. Initially, the effects of the dispersant type and content on the rheology, sedimentation, and curing properties of the Si 2 N 2 O ceramic slurry were investigated. The results revealed that 4 wt% KH570 included as an additive could effectively improve the compatibility between the Si 2 N 2 O powder and resin, imparting good fluidity to the prepared slurry. Furthermore, the UV absorption of the Si 2 N 2 O powder at 450 nm decreased from 0.24 to 0.11, which was conducive for improving the curing properties of the Si 2 N 2 O ceramic slurry. Subsequently, the effects of the sintering additives, holding time, and sintering temperature on the properties of the porous Si 2 N 2 O ceramics were investigated. Finally, a Si 2 N 2 O ceramic slurry with a solid content of 40 vol% was prepared using 5 wt% Al 2 O 3 as a sintering agent. Upon sintering at 1600 °C for 3 h, a Si 2 N 2 O ceramic body with a porosity of 7.26 %, density of 87.54 %, and flexural strength of 207 MPa was obtained.